Tubular writing point especially for automatic drafting machines

ABSTRACT

A tubular writing instrument, having a clearing wire with drop weight and being adapted for use in automatic drafting machines.

Umted States Patent 1 [111 3,734,633

Anderka 1 1 May 22, 1973 54] TUBULAR WRITING POINT [56] References CitedESPECIALLY FOR AUTOMATIC UNITED STATES PATENTS Inventor; Gem Anderka,Hamburg 3,539,269 11/1970 D ahle ..401/259 many 3,466,132 9/1969 R1epe..401/259 2,217,502 10/1940 Wallace ..401/259 [73] Assignee: Koh-I-NoorRapidograph Ince 3,459,486 8/1969 Matschkal ..401/259 Bloomsbury, NJ.3,561,880 2/1971 Bok ..401/258 1 Filedl 1 1971 FOREIGN PATENTS ORAPPLICATIONS [211 APPl- 117,617 1,534,861 6/1968 France ..401/258Foreign Application Priority Data Primary Examiner-Lawrence Charles Mar.5, 1970 Germany ..P 20 10 355.3 Semmes pr 30, 9 Germany P2021 1534 [5ABSTRACT US. A tubular instrument having a clearing wire Int. Cldropweight and being adapted for use in auto- [58] Field of Search..401/258-260 matic drafting machines 12 Claims, 5 Drawing FiguresPATENTEL MAY 2 21975 SHEET 1 BF 3 N Qk INVENTOI GEROLD ANDERKA ATTORNEYPAIENTE W22 197s SHEET 2 BF 3 r/K//////////X//////// ATTORNEY pmmmwzzms3,734,533

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mvzu'roa GEROLD ANDERKA ATTORNEY TUBULAR WRITING POINT ESPECIALLY FORAUTOMATIC DRAFIING MACHINES This invention relates to a tube writinginstrument particularly for use in automatic drawing machines but alsoadapted to be used as a manual implement.

It has previously been proposed to provide a tube writing implementcontaining a cartridge for ink in a holder or a holder forming an inkreservoir, the implement comprising a cylindrical member which at oneend forms a mount for the reception of a writing tube, and whichcontains an internal bore for the accommodation therein of a drop weightcarrying a clearing wire, and a thread cut into the external wall of thecylindrical member to .form acompensating chamber communicating with theinternal bore through one or more radial ducts. Such tube writingimplements have the defeet that the thread forming the compensatingchamber becomes blocked with deposits of ink which then prevent thecylindrical member from being easily unscrewed or extracted.

According to the present invention there is provided a tube writingimplement, comprising a cylindrical member which at one end forms amount for a writing tube, and which contains an internal bore for thereception of a drop weight carrying a clearing wire, a thread beingformed in the external wall of the cylindrical member to form acompensating chamber communicating with the internal bore through one ormore radial ducts, and a ring or sleeve having an internal screw threadscrewable on a co-operating external screw thread formed on thecylindrical member in the region of the compensating chamber, the ringor sleeve being arranged to cover the compensating chamber.

By covering only the compensating chamber with such a ring or threadedsleeve, the threads of the compensating chamber can be exposed forcleaning simply by unscrewing the .sleeve or ring, without the distanceof the writing tube proper or of the cylindrical member from the drawingsurface being changed.

Preferably an annular shoulder against which the ring or sleeve can abutis formed the cylindrical member rearwards of the compensating chamber.The position of the ring, when this is screwed tight, is thus preciselydefined and a tight joint is formed.

In order to prevent the tube writing implement, when an attempt is madeto unscrew the ring, from being screwed out of its holder instead of theringer sleeve being unscrewed from the cylindrical member, by reason ofthe ring or sleeve being firmly stuck to the cylindrical member byhardened deposits of ink or, conversely the ring or sleeve from beingunscrewed when an attempt is made to unscrew the tube writing implementfrom its holder, it is desirable that the hand of the threads forscrewing the tube writing implement to its holder should be contrary tothe hand of the external thread in the region of the compensatingchamber. Preferably the external thread in the region of thecompensating chamber is a left-hand thread.

In such an arrangement it is then possible, as desired, either tounscrew the ring or sleeve from the cylindrical member or the entiretube writing implement from its holder, and to avoid both these eventstaking place at the same time. For instance, when it is desired tounscrew the ring or sleeve from the cylindrical member, the appropriaterotation of the ring or sleeve results in the rest of the tube writingimplement being turned even more tightly into its holder instead ofbeing unscrewed together with the ring or sleeve. Conversely, unscrewingof the tube writing implement from its holder results in the ring orsleeve being even more securely tightened on the cylindrical member.

Since normally the tube writing implement will be more frequentlyunscrewed from its holder than the ring or sleeve from the cylindricalmember for cleaning the compensating chamber, the threads for securingthe tube writing implement to its holder are preferably right-handthreads so that the user can secure and unscrew the tube writingimplement by screwing in the generally conventional hand of rotation.

Moreover, in tube writing implements used in automatic machines, it isdesirable to fit the annular shoulder with or to embed in the same aconcentric metal ring. The purpose of this metal ring is to guide andcentrally to align the entire tube writing implement radially in theholder of the automatic drawing machine.

For the purpose of centring the writing tube in automatic drawingmachines, the tube is preferably designed to merge into a cylindricalmetal shoe which has a radius that exceeds the radius of the tube, andwhich is formed with projections or with a peripheral axial face forsupporting the same axially in a tapering forward part of thecylindrical member.

The feature that the metal shoe, irrespective of the radius of thewriting tube, has a particular radius for its abutting face, facilitatesadjustment in the lower region of the tube writing implement and avoidsthe necessity for readjustment each time a writing tube for a differentline thickness is to be used. Moreover, the fact that the metal shoe hasprojections or a peripheral axial face is a matter of importance inautomatic drawing machines. Generally, the writing tube has, in thepast, been inserted without a change in section into the tapering part,i.e. the conical forward end, of the cylindrical member. Owing to therelatively heavy jolt of application of the writing tube to the paper inautomatic drawing machines, the point of the writing tube may be axiallyshifted, so that an axial butt face can provide support by bearingagainst the cylindrical member and prevent axial displacement.Furthermore, for improving the axial location of the writing tube, thecylindrical end of the tube extending into the tapering end may beformed with one or more peripheral slots.

In the present tube writing implement ink is supplied either from an inkcartridge which is fitted onto a cylindrical extension of thecylindrical member to the rear of the annular shoulder that may carry acentring ring, or an external thread may be formed on or to the rear ofthe annular shoulder for the screw attachment thereto of a holderforming an ink reservoir or contain ing such a reservoir. Both forms ofconstruction can be adopted for tube writing implements used inautomatic drawing machines or for normal tube writing pens for manualdrawing.

Finally it may be desirable to fit or screw into the rear end of theinternal bore which serves as an ink chamber, a ring having an internaldiameter that is smaller than that of the drop weight. This ring willthen prevent the drop weight from falling out.

In order to enable the invention to be more readily understood,reference will now be made to the accompanying drawings, whichillustrate diagrammatically and by way of example some embodimentsthereof, and in which:

FIG. 1 is a part longitudinal section through a tube writing implementfitted with a ring that covers a compensating chamber and having anannular shoulder carrying a centring ring,

FIG. 2 is a section similar to that shown in FIG. 1, of

a tube writing implement in which an annular shoulder bears threads forthe screw attachment thereto of a holder,

FIG. 3 is a detail showing the construction of a mount for a writingtube and a metal shoe,

FIG. 4 is a view similar to FIG. 3 of an embodiment in which a writingtube mount is formed with internal circumferential slots, and

FIG. 5 is a detail similar to FIG. 3 of an embodiment in which anannular axial face is differently formed.

Referring now to FIGS. 1 and 2, there is shown in each of these FIGS. atube writing implement comprising a cylindrical member 2 having an axialbore 4 containing a drop weight 6. The latter has a reduced for- Y wardend 8 which carries a clearing wire 10. The forward end 12 of thecylindrical member 2 is of conical tapering configuration, and themember is formed with a thread 14 which serves as a compensating chamberand which communicates with the internal bore 4 through radial ducts 16.In proximity with the compensating chamber 14, an external thread 13 isprovided for a ring 1 having a corresponding internal thread to bescrewed on the cylindrical member 2. The ring 1 cannot be screwed on thecylindrical member 2 further than into contact with an annular shoulder18 of the cylindrical member or an interposed ring 22. In tube writingimplements intended for automatic drawing equipment a metal ring 20(FIG. 1) is inserted or cast onto this annular shoulder 18, the metalring being precision machined so that it is in exact concentric axialalignment. An intermediate ring 22 which may bear a color code may belocated on the front face of the annular shoulder 18.

The rear end of the cylindrical member 2 is open to a main inkreservoir, for instance to a cartridge 28 (FIG. 2) containing Indian inkand mounted on a cylindrical extension 26 of the member 2. In order toprevent the drop weight 6 from falling out, the opening into thecylindrical bore may be constricted by the insertion of a ring 24 whichhas an internal diameter less than the external diameter of the dropweight and which also serves as a stop for retraction of the drop weightto control the flow of ink. I

If desired, external threads 32 may be provided to the rear of theannular shoulder on the extension 26 or, as shown in FIG. 2, on theannular shoulder 18 itself for the afiixation thereto of a barrel 5 thatis conventional in ordinary hand-held pens. If such a barrel isprovided, the presence of the ink cartridge 28 is not essential, sincethe barrel may be arranged to serve as an ink reservoir.

In the embodiment shown in FIG. 2, the threads 32 and the externalthreads 13 may be of opposite hand. For example, if the threads 32 areright-handed and the external threads 13 are left-handed then the entiretube writing implement can be screwed into the barrel and screwed out ofthe barrel in the normal direction of rotation.

For instance, when it is desired to remove the tube writing implementfrom the barrel 5, then this would be done by anticlockwise rotation (asviewed from the end 38 of the writing tube). This hand of rotation isthe same as the direction of rotation for screwing the ring 1 tight,this ring having a left-handed thread. Hence the latter will not beslackened off when the tube writing implement is unscrewed from thebarrel 5. The same naturally also applies to the unscrewing of the ring,which is accomplished by turning it in the direction in which the tubewriting implement is screwed into the barrel.

Screw threads 7 for mounting a protective cap (not shown) are preferablyright-handed if the external threads 13 are left-handed. This preventsthe ring from being slackened off when the protective cap is removed.

The writing tube merges into a metal shoe 40 which is inserted into thetapering forward end 12 of the cylindrical member 2. In order to preventthe continuous shocks experienced in automatic drawing machines when thepen is suddenly dropped on the sheet from displacing the writing tube 38and its shoe 40, the latter is formed with an axial abutment face 42which bears against the conically tapering forward end 12 of thecylindrical member. This may be arranged as is shown in FIG. 3, wherethe shoe 40 has a larger diameter than the end 44 extending into thetapering end 12. An annular abutment face 42 is thus formed which bearsagainst the front face of the tapering forward end 12. Alternatively thearrangement may be as illustrated in FIG. 4 where annular slots 42"provide the necessary safety device for preventing axial displacement ofthe shoe of which part is moulded into the tapering forward end 12.Finally, another alternative is that shown in FIG. 5 in which the shoeis integrally formed with a collar 42 which similarly serves the desiredpurpose.

What we claim is:

1. A tube writing implement comprising:

A. a cylindrical member forming at one end thereof a writing tube mount;

B. a writing tube in said tube mount;

C. an internal bore in said cylindrical member;

D. a drop weight in said cylindrical bore and mounting thereon aclearing wire operatively extending in said writing tube;

E. a thread in the external wall of said cylindrical member forming acompensating chamber, and radial ducts intercommunicating said threadand the internal bore;

F. said cylindrical member having an external screw thread over the areaof said compensating chamber;

G. an internally screw threaded sleeve removably engaged on saidexternal screw thread and covering said compensating chamber;

H. said cylindrical member having external ink reservoir mountingthreads on the end thereof opposite the writing tube mount; and

I. an ink reservoir operatively removably associated with said inkreservoir mounting threads.

2. A tube writing implement as claimed in claim 1, wherein an annularshoulder, against which the sleeve can abut, is formed on thecylindrical member to the rear of the compensating chamber.

3. A tube writing implement as claimed in claim 2, wherein a concentricmetal ring is fitted on the annular shoulder.

4. A tube writing implement as claimed in claim 1, wherein the writingtube merges into a cylindrical metal shoe having a radius that exceedsthe radius of the tube, and said shoe having an annular projection toprevent the shoe from being axially displaced inside a tapering part ofthe cylindrical member.

5. A tube writing implement as claimed in claim 4, wherein the shoe ofthe writing tube is formed with peripheral annular slots for preventingaxial displacemerit.

6. A tube writing implement as claimed in claim 5, wherein the writingtube together with its shoe is moulded into the tapering part of thecylindrical member.

7. A tube writing implement as claimed in claim 2, wherein rearwards ofthe annular shoulder the cylindrical member has a cylindrical extensionfor attachment thereto of an ink cartridge.

8. A tube writing implement as claimed in claim 1, wherein thecylindrical member is formed with threads for screwing the tube writingimplement into a holder.

9. A tube writing implement as claimed in claim 8, wherein the hand ofthe threads for screwing the tube writing implement to a holder iscontrary to the hand of the external thread in the region of thecompensating chamber.

10. A tube writing implement as claimed in claim 9, wherein the externalthreads are left-hand threads.

11. A tube writing implement as claimed in claim 3, wherein anintermediate ring is provided between the annular shoulder and sleeve.

12. A tube writing implement as claimed in claim 1, wherein a ringhaving an internal diameter smaller than the diameter of the drop weightis tightly fitted into the rear end of the internal bore which serves asan ink chamber and serves as a stop for retraction of said drop weight.

1. A tube writing implement comprising: A. a cylindrical member formingat one end thereof a writing tube mount; B. a writing tube in said tubemount; C. an internal bore in said cylindrical member; D. a drop weightin said cylindrical bore and mounting thereon a clearing wireoperatively extending in said writing tube; E. a thread in the externalwall of said cylindrical member forming a compensating chamber, andradial ducts intercommunicating said thread and the internal bore; F.said cylindrical member having an external screw thread over the area ofsaid compensating chamber; G. an internally screw threaded sleeveremovably engaged on said external screw thread and covering saidcompensating chamber; H. said cylindrical member having external inkreservoir mounting threads on the end thereof opposite the writing tubemount; and I. an ink reservoir operatively removably associated withsaid ink reservoir mounting threads.
 2. A tube writing implement asclaimed in claim 1, wherein an annular shoulder, against which thesleeve can abut, is formed on the cylindrical member to the rear of thecompensating chamber.
 3. A tube writing implement as claimed in claim 2,wherein a concentric metal ring is fitted on the annular shoulder.
 4. Atube writing implement as claimed in claim 1, wherein the writing tubemerges into a cylindrical metal shoe having a radius that exceeds theradius of the tube, and said shoe having an annular projection toprevent the shoe from being axially displaced inside a tapering part ofthe cylindrical member.
 5. A tube writing implement as claimed in claim4, wherein the shoe of the writing tube is formed with peripheralannular slots for preventing axial displacement.
 6. A tube writingimplement as claimed in claim 5, wherein the writing tube together withits shoe is moulded into the tapering part of the cylindrical member. 7.A tube writing implement as claimed in claim 2, wherein rearwards of theannular shoulder the cylindrical member has a cylindrical extension forattachment thereto of an ink cartridge.
 8. A tube writing implement asclaimed in claim 1, wherein the cylindrical member is formed withthreads for screwing the tube writing implement into a holder.
 9. A tubewriting implement as claimed in claim 8, wherein the hand of the threadsfor screwing the tube writing implement to a holder is contrary to thehand of the external thread in the region of the compensating chamber.10. A tube writing implement as claimed in claim 9, wherein the externalthreads are left-hand threads.
 11. A tube writing implement as claimedin claim 3, wherein an intermediate ring is provided between the annularshoulder and sleeve.
 12. A tube writing implement as claimed in claim 1,wherein a ring having an internal diameter smaller than the diameter ofthe drop weight is tightly fitted into the rear end of the internal borewhich serves as an ink chamber and serves as a stop for retraction ofsaid drop weight.